1. Field of the Invention
The invention relates to a caliper brake assembly particularly adapted for use in heavy duty disc brake assemblies such as in winches and cable systems.
2. Prior Art
Caliper brakes have been used for many years in disc brake assemblies in which a pair of opposed arms hinged to a frame carry brake shoes at inner ends thereof and are rotated about a hinge axis by a brake actuator, such as a fluid actuated cylinder, extending between outer ends thereof. Braking force obtained in this type of assembly is proportional to cross-sectional area of the actuator, and ratio of moment arms of the brake shoes and actuator about the hinge axis. It can be seen that, for use in a heavy duty application in which high braking forces are required, a relatively large actuator acting on relatively long arms is needed. In the past, sometimes difficulty has been experienced in accommodating heavy duty calipers in a restricted space because of the size of the components necessary to obtain the required braking force.
Often a disc brake is to be used for dynamic braking only, and a separate mechanically-actuated band brake or drum brake is required for static braking in which the brake is to be locked on or engaged for long periods. This is because adequate braking force can only be obtained with the disc brake by using a pressurized fluid, and where fluid pressure lost in a static brake cannot be tolerated for safety reasons, mechanically actuated brakes are required. Using a second brake for static braking only is costly and aggravates design difficulties when there are severe space limitations in the brake installation.